Process for dyeing a mixture of two or more different fibre types

ABSTRACT

The invention relates to a process for dyeing a mixture of two or more different fibre types with one or more dyes. The process according to the invention is characterized in that the mixture contains a portion of cationized cellulosic fibres. Furthermore, the invention relates to fibre blends obtainable by the process according to the invention.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/AT2004/000084 filed Mar. 11, 2004, designating the United Statesand published in the German language on Sep. 23, 2004 underInternational Patent Publication No. WO 2004/081279, which is based onAustrian Patent Application No. A 400/2003 filed Mar. 13, 2003, to eachof which priority is claimed, and each of which is incorporated byreference in its entirety herein.

FEDERALLY FUNDED GRANT SUPPORT

Not applicable.

1. INTRODUCTION

The present invention relates to a process for dyeing a mixture of twoor more different fibre types as well as fibre blends.

2. BACKGROUND OF THE INVENTION

Conventionally mixtures of fibres of different origins are used toproduce textiles such as woven fabrics or knitted fabrics. Furthermore,it is known that by using differently dyed fibres or yarns it ispossible to achieve colour effects in the textiles. However, it islaborious that the starting products for the production of the textile,i.e. the fibres or yarns, respectively, often have to be dyed withdifferent dyes separately from each other so as to achieve the desiredeffect in the fabric. In particular when manufacturing a so-called denimfabric, the warp yarn must be warp-dyed in the exhaust process duringthe indigo dyeing process, i.e. it is not feasible to dye finishedcloths. Such problems arise especially when using cellulosic fibres suchas viscose fibres, Lyocell fibres but also cotton fibres. The object ofthe present invention is to provide a process for dyeing a mixture oftwo or more different fibre types with one or more dyes, by means ofwhich process the disadvantages discussed above can be overcome.

3. SUMMARY OF THE INVENTION

The object of the present invention is to provide a process for dyeing amixture of two or more different fibre types with one or more dyes, bymeans of which process those disadvantages can be overcome.

4. DETAILED DESCRIPTION OF THE INVENTION

It has been shown that, by using cationized cellulosic fibres, variousproblems associated with the production of textile products showingcolour effects can be solved or new possibilities can be opened up, inparticular:

-   -   the attainment of differences in colour intensity (Differential        Dyeing) between two fibre types (a cationized cellulosic fibre        and another, especially cellulosic, fibre) with only one dye        being used    -   the attainment of mixed colours when dyeing with several dyes,        whereby the different fibre types are each coloured differently        or optionally not at all, respectively, with the dyes being used    -   an acceleration of the dyeing process when dyeing mixtures of        cationized cellulosic fibres and synthetic fibres such as        polyester fibres or polyamide fibres.

Cationized cellulose fibres are known per se. Fibres which incorporatethe cationic groups are particularly preferred for use in the processaccording to the invention. Such fibres are manufactured in that acationizing agent which is stable in the respective manufacturingprocess is added to the spinning dope for producing the fibre or to aprecursor of said spinning dope.

Furthermore it is known that cationized cellulose fibres exhibitparticular colouring properties which differ from those ofnon-cationized cellulose fibres.

Cationized viscose fibres, i.e. fibres which were produced by theviscose process and which carry cationic groups, are particularlypreferred for use in the process according to the invention.

The manufacture of cationized cellulosic fibres is known per se and isdescribed, for instance, in JP-A 61-258801, JP-A 52-26561, JP-A2-274738, EP-A 0 683 251, EP-A 0 690 166 or WO 96126220.

In a prefesred embodiment of the process according to the invention, themixture contains a portion of non-cationized cellulosic fibres. Thenon-cationized cellulosic fibres may be selected from the groupconsisting of standard viscose fibres, modal fibres, Lyocell fibres,cotton fibres and linen fibres.

Due to the varying colouring properties of cationized cellulose fibresand non-cationized cellulose fibres, interesting colour effects can beachieved in a simple manner, f.i. , when colouring with only one dye.

The process according to the invention can be realized effectively inthat the mixture is dyed with a direct dye and/or a reactive dye.

Cationized cellulose fibres, in particular cationized viscose fibres,are coloured more intensely by direct dyes and reactive dyes thannon-cationized cellulose fibres.

Surprisingly, the achievable mixed-colour effect thereby dependsparticularly strongly on the salt concentration used for dyeing (lessstrongly on the pH value and the temperature of dyeing). Theconcentration of the dye in the batch also plays a role, with thedifference in colour depth between the fibres decreasing, the greaterthe dye concentration.

When dyeing with direct dyes, the mixed-colour effect is particularlypronounced at low salt concentrations of 3 to 5 dl. At higher saltconcentrations of up to 25 dl, on the other hand, almost equal colourdepths of the cationized and the non-cationized cellulose fibres areachieved.

When dyeing with reactive dyes, the mixed-colour effect is particularlypronounced at salt concentrations of up to 20 g/l. At higher saltconcentrations of up to 80 g/l, almost equal colour depths of thecationized and the non-cationized cellulose fibres are achieved.

Furthermore, it can be shown that the mixed-colour effect is morestrongly pronounced if modal fibres or cotton fibres are used asnon-cationized cellulosic fibres than if standard viscose fibres orLyocell fibres are used.

Interesting effects are also achieved if a mixture of cationizedcellulose fibres and noncationized cellulose fibres is dyed with twodifferent reactive dyes. In doing so, dyeing can be carried out firstwith one of the reactive dyes under conditions in which only thecationized cellulose fibre is coloured. Subsequently, the secondreactive dye is added, and dyeing is carried out under conditions inwhich both the cationized cellulose fibre and the non-cationizedcellulose fibre are coloured.

Another aspect of the process according to the invention ischaracterized in that the mixture is dyed with a wool dye and at leastone other dye, in particular a direct dye and/or a reactive dye. Also inthis embodiment, the use of a fibre blend containing cationizedcellulose fibres and non-cationized cellulose fibres is particularlysuitable.

Under wool dyes, a person skilled in the art will understand dyes bymeans of which it is feasible to dye wool or polyarnide. Among those areacid dyes, metallized dyes and acid reactive dyes. It is particularlypreferred to use a metallized dye as a wool dye.

While the non-cationized cellulose fibres in a mixture of cationizedcellulose fibres and noncationized cellulose fibres virtually fail to becoloured by the wool dye, the cationized cellulose fibres are colouredby the wool dye.

The non-cationized cellulose fibres are coloured by the second dye thatis used (preferably a direct dye or a reactive dye) at appropriatedyeing conditions. Said second dye optionally also colours thecationized cellulose fibre at least partially.

Thus, on the one hand, a mixed colouring between cationized andnon-cationized cellulose fibres is created. On the other hand, a mixedcolour is optionally also created in the cationized cellulose fibresitself as a result of dyeing with the wool dye and the competing dyeingprocess involving the second dye.

If a dye that is used is a metallized dye, the use of Lyocell fibres asthe non-cationized cellulosic fibres in the mixture has provenfavourable, since those fibres are stained the least by the metallizeddye.

Another preferred embodiment of the process according to the inventionis characterized in that the fibre blend contains a portion ofnon-cellulosic fibres. In this respect, in particular polyester fibres(PES) or polyamide fibres (PA) appear to be interesting for differentapplications. Thereby, in particular mixtures of two components(cationized cellulose fibre/synthetic fibre) or three components(cationized cellulose fibre 1 non-cationized cellulose fibre/syntheticfibre) are advantageous.

It can be shown, for example, that the duration of the dyeing processcan be drastically reduced if a mixture of cationized cellulose fibresand polyester fibres is dyed with reactive dyes under the conditions ofreactive dyeing.

In doing so, the achievable effects are dependent on differentparameters depending on the components and types of dyes that are used.In the following table, the influence of the dyeing temperature and thepH value on various embodiments of the process according to theinvention is demonstrated. TABLE 1 Behaviour during competing dyeings ofcationized cellulose and non-cationized Cationized Non-CationizedCationized Non-Cationized cellulose cellulose cellulose cellulosecellulose Dyeing temperature T = 80-90° C. T = 80-90° C. T = 110-130° C.T = 110-130° C. Wool dyes is dyed is no dyed is dyed is not dyed(metallized dyes) completely completely Direct dyes is dyed is dyed fromslightly is dyed is dyed from slightly completely to completelycompletely to not at all depending on the depending on the saltconcentration salt concentration Reactive dyes is dyed is dyed frommoderately is dyed is dyed from slightly completely to completelycompletely to not at all depending on the depending on the saltconcentration salt concentration Behaviour during cationized polyamidecationized polyamide competing dyeings of cellulose cellulose cationizedcellulose and polyamide pH value 4 to 6 4 to 6 9 to 11 9 to 11 Wool dyesis dyed from is dyed is dyed is dyed from (metallized dyes) slightly tocompletely completely slightly to not at all not at all

The table shows in particular that, in case of mixtures of cationizedand non-cationized cellulose fibres, there are differences in thecolouring behaviour above and below a dyeing temperature of 100° C.

The fibre blend may be dyed in the form of a yarn or a part of a yarn,respectively, or in the form of a textile or a part of a textile,respectively.

It is particularly preferred that the fibre blend is dyed in the form ofa fabric so as to achieve a denim effect.

At present, the indigo effect desireable for jeans fabrics is achievedby an indigo dyeing process. Should one wish to dye indigo continuouslyon cellulosic fibres, an elaborate multistage process is necessary. Awarp-dyeing process must be carried out, i.e. it is not feasible to dyefinished cloths.

It has been shown that in particular mixed fabrics made of cationizedcellulose fibres, polyester fibres and cotton fibres may be dyed suchthat the specific indigo effect can be achieved without multi-stageindigo dyeing and on an already finished cloth.

Furthermore, it is possible to achieve specific and selective melangeeffects. Also the wearability of pieces of clothing made of blendedfabrics dyed in such a manner is better, as a softer and more pleasantfeel can be achieved. In addition, another result is a better washingresistance in comparison with that of standard indigo products.

It can be shown that the mixed colourings achievable by the processaccording to the invention are excellently reproducible.

Furthermore, the invention relates to a fibre blend obtainable inaccordance with the process according to the invention.

Furthermore, the invention relates in particular to a fibre blendcontaining a portion of cationized cellulosic fibres and a portion ofnon-cationized cellulosic fibres, which fibre blend is characterized inthat the portion of cationized cellulosic fibres and the portion ofnon-cationized cellulosic fibres are coloured with the same direct dyeand/or a reactive dye and that there is a difference in the colouringintensity between the portion of cationized cellulosic fibres and theportion of non-cationized fibres.

As described above, it is possible to control the varying degree ofcolouring in particular by selecting the salt concentration for thedyeing process.

Said embodiment of the fibre blend according to the invention ispreferably characterized in that the difference in the colouringintensity between the cationized cellulosic fibres and thenon-cationized fibres amounts to 5 to 50 CIELAB units according to themeasuring method as indicated below.

Another preferred embodiment of the present invention relates to a fibreblend containing a portion of cationized cellulosic fibres and a portionof non-cationized cellulosic fibres, which fibre blend is characterizedin that the portion of cationized cellulosic fibres is coloured with awool dye and optionally at least partially with another dye, inparticular a direct dye and/or a reactive dye, whereas the portion ofnon-cationized fibres is coloured only by said other dye. As alreadydescribed before, interesting colour effects can be achieved in a simplemanner with such fibre blends.

Fibres from the group consisting of standard viscose fibres, modalfibres, Lyocell fibres, cotton fibres and linen fibres can be includedas non-cationized cellulosic fibres.

In the fibre blends according to the invention, the cationizedcellulosic fibres preferably incorporate the cationic groups.

Furthermore, it is preferred that the cationized cellulosic fibres arecationized viscose fibres. The fibre blends according to the inventionpreferably contain a portion of non-cellulosic fibres such as polyesterfibres or polyamide fibres.

A particularly preferred embodiment of the fibre blend according to theinvention is provided in the form of a denim fabric.

In the following, preferred embodiments of the present invention areexplained in greater detail by way of exemplary embodiments.

All the cationized viscose fibres mentioned in the following exampleswere produced in accordance with processes described in WO 96126220.

5. WORKING EXAMPLES

Preferred embodiments of the invention are explained in more detail byway of the following examples.

Example 1

A fabric consisting of a mixture of standard viscose fibres andcationized viscose fibres was dyed at a dyeing temperature of 80° C.with a dye bath containing 2% dye (Sirius Rubin K-2BL -direct dye,manufacturer Messrs. DyStar), based on 20 g of fabric (600 ml batch),and a nonionic wetting agent at various salt concentrations (Na₂SO₄).

The brightness of the coloured standard viscose fibres and thecationized viscose fibres, respectively, was measured according to thefollowing measuring method:

The CIELAB whiteness of the fibres was determined according to thefollowing method:

The colour coordinates of the fibres according to R_(x), R_(y), R_(z)were determined according to DIN 6174 and DIN 5033 with illuminant D65and at an observation angle of 10°. From those colour coordinates, theCIE whiteness and the colour cast in the redlgreen axis are computedaccording to DIN 55981 (=colour drift according to GartnerIGriesser) asfollows:

CIE whiteness: W=Y+800″(x_(o)−x)+1700 (y_(o)−y)

Colour cast (=tint): T=900*(x_(o)−x)−650″(y_(o)−y)

(Note: T negative=red tinge, T positive=green tinge)

Y . . . standard colour value for the green sensitivity(=R_(y).reflectance value green)

x_(o)y_(o), . . . standard colour value parts of the achroniatic point(at D65/10° the following is valid:

x_(o)=0.3138; y_(o)=0.3310)

x,y . . . standard colour value parts of the samples, to be computedaccording to:x=X/(X+Y+Z)y=U/(X+Y+Z)2=1−x−y

The standard colour values X, Y, Z, appearing in those formulas, are inturn computed from the reflectance values (=filter values) R_(x), R_(y),R_(z), at illuminant D65 and at an observation angle of 10° according tothe formulas:X=0.94811*R_(x)Y=R_(y)Z=1.07304* R_(z)

In the following table, the respective difference in the CIELABbrightness evaluated for the two dyed fibre types is indicated -depending on the salt concentration that is used: TABLE 2 Difference inbrightness Salt concentration (g/l) (CIELAB units) 2 10 5 7 10 6 20 4.5

Example 2

Fabrics consisting of

-   -   cationized viscose fibres;    -   weakly fibrillating Lyocell fibres (type “Lyocell LF”,        manufacturer Lenzing AG); and    -   modal fibres (manufacturer Lenzing AG).

were each dyed with two types of dye, namely with a direct dye (Siriusdyes, manufacturer Messrs. DyStar) and a metallized dye (Isolan dyes,manufacturer Messrs. DyStar), with the dye bath containing both dyes.The following standard parameters were maintained: Liquor ratio: 10 gfabric with 600 ml batch Nonionic wetting agent Salt content: 10 g/l pHvalue: 7 Dyeing temperature: 80° C. Duration of dyeing: 45 min

Dyeings were carried out with batches containing the following dyes:

-   2.0% Sirius yellow K-GRL; 0.15% Isolan dark blue 2s-GL 01-   2.0% Sirius yellow K-GRL; 0.4% Isolan dark blue 2s-GL 01-   2.0% Sirius yellow K-GRL; 0.8% Isolan dark blue 2s-GL 01-   2.0% Sirius yellow K-GRL; 0.4% Isolan bordeaux R 220%-   2.0% Sirius yellow K-GRL; 0.8% Isolan bordeaux R 220%-   2.0% Sirius yellow K-GRL; 0.8% Sirius turquoise GL 01-   2.0% Sirius yellow K-GRL; 0.8% Isolan grey S-GL-   1.0% Sirius blue K-GRL; 1.5% Isolan yellow K-GLN 250%-   1.0% Sirius blue K-GRL; 0.5% Isolan yellow K-GLN 250%-   1.0% Sirius blue K-GRL; 1.0% Isolan scarlet K-GLS 150%-   1.0% Sirius blue K-GRL; 0.5% Isolan scarlet K-GLS 150%-   1.0% Sirius blue K-GRL; 1.5% Isolan grey S-GS-   1.5% Sirus scarlet K-CF; 1.0% Isolan yellow K-GLN 250%-   1.5% Sirus scarlet K-CF; 0.5% Isolan yellow K-GLN 250%-   1.5% Sirus scarlet K-CF; 0.8% Isolan olive SG-   1.5% Sirus scarlet K-CF; 0.2% Isolan olive SG-   1.5% Sirus scarlet K-CF; 0.15% Isolan dark blue 2s-GL 01-   1.5% Sirus scarlet K-CF; 1.5% Isolan grey S-GL

In all cases, the non-cationized cellulose fibres (Lyocell or modal,respectively) were coloured virtually exclusively with the direct dye;in addition, the cationized viscose fibres were coloured with themetallized dye, whereby - depending on the colour and concentration ofthe dyes that were used - mixed colourings controllable in wide areasemerged in the cationic fibres.

Those mixed colourings (and the difference in colour between thecationized viscose fibre and the other cellulose fibre) produceinteresting effects in fabrics which contain a mixture of those twofibres and are dyed with the above-mentioned dyes.

Similar effects were observed inl analogous tests involving fabrics madeof cationized viscose fibres and cotton fibres.

Example 3

Striped socks (alternately 1 cm of cationized viscose fibres and 1 cm ofLyocell fibres) were manufactured and dyed with the following dyemixtures:

3a) 2.0% Sirius yellow K-GRL; 0.15% Isolan dark blue 2s-GL 01

3b) 2.0% Sirius yellow K-GRL; 0.4% Isolan bordeaux R 220%

The dyed striped socks exhibited striped areas with markedly differentcolourings. In example 3a), the sections of the Lyocell fibres were eachdyed yellow; the sections of the cationized viscose fibres eachexhibited a green mixed colour (from the yellow direct dye and the bluewool dye).

In example 3a), the sections of the Lyocell fibres were also each dyedyellow; the sections of the cationized viscose fibres each exhibited anorangelreddish mixed colom (from the yellow direct dye and the red wooldye).

Furthermore,

-   -   knitted stockings made of a yarn containing cationized viscose        fibres and Lyocell fibres (Nm 5011);    -   twill fabrics 311 made of a twisted yarn (Nm 5012)—a mixture of        cationized viscose fibres and Lyocell fibres—in the woof and        modal fibres in the warp; and    -   herringbone fabrics made of a twisted yarn (Nm 5012)—a mixture        of cationized viscose fibres and Lyocell fibres—in the woof and        modal fibres in the warp. were dyed with the dye mixtures        described above, whereby also interesting colour effects        resulted.

In all cases, the mixed colourings that were achieved were excellentlyreproducible, i.e. a repetition of the test yielded virtually identicaldyeing results.

Example 4

A knitted fabric made of a twisted yarn—containing cationized viscosefibres and cotton fibres at a ratio of 50150—and a PES filament was dyedin a bath first under the dyeing conditions for PES fibres (i.e. at 130°C.) with a dye complex consisting of a metallized dye and a disperse dyeand subsequently at 90° C. with a direct dye at a salt concentration of7 g/l of salt. The procedure of dyeing can be illustrated as follows:

-   -   start: temperature 50° C., dye bath: metallized dye+disperse        dye; 20 g/l Na-acetate, dispersing agent: Setamol NS    -   heating to 130° C.    -   dyeing within 30-45 min    -   cooling to 50° C.    -   adding dye bath with direct dye, 7 g/l of salt    -   heating to 90° C.    -   dyeing within 30 min    -   cooling

The following dye combinations were chosen:

4a) 2.0% Sirius yellow K-GRL (direct dye); 0.4 Isolan bordeaux R 220%(metallized dye)

4b) 2.0% Sirius yellow K-GRL (direct dye); 0.8% Supranol turquoise GGL(metal complex; manufacturer: Messrs. DyStar)

A black disperse dye (Dianix Schwarz CC, manufacturer Messrs. DyStar)was selected as the disperse dye for the PES fibres.

As a result, fabrics with interesting mixed colourings were obtained,wherein the PES filament was dyed black with the disperse dye; thecationized viscose fibre was mixed-dyed with the metallized dye and thedirect dye; the cotton fibres were coloured only with the direct dye.

Example 5

In order to achieve a denim effect, a fabric consisting of a mixture ofcationized viscose fibres and PES fibres (60140) in the warp and cottonfibres in the woof was dyed, such as described in example 4, first underthe dyeing conditions for PES fibres with a dye mixture from a dispersedye and a metallized dye.

The samples dyed in this way correspond to the results of astandard-indigo-denim production, if equal tints were used for thedisperse dye and the metallized dyes. By using different tints melangeoptics are generated, the obtainment of which by an indigo-standardtechnology would be very laborious and expensive. Subsequently, a fewmore samples were dyed with direct dyes in the same bath, immediatelyupon the PES dyeing. Thereby, it is possible to dye also the cottoncomponent in the same dyeing process.

The monobath, approximately one-hour long competing dyeing processdescribed above can be regarded as an interesting alternative to thelaborious and technically demanding indigo dyeing process. Moreover, thedyeing processes according to the invention for producing a denim effectoffer an outstandingly good flexibility, since no previous warp dyeingis necessary and hence a quick and efficient adjustment to the marketbecomes possible.

1-20. (canceled)
 21. A dyeing process comprising dyeing a mixture of twoor more different fiber types with one or more dyes, wherein the fibermixture comprises a portion of cationized cellulosic fibers.
 22. Adyeing process according to claim 21, wherein the cationized cellulosicfibers comprise cationic groups.
 23. A dyeing process according to claim21, wherein the cationized cellulosic fibers are cationized viscosefibers.
 24. A dyeing process according to claim 21, wherein the mixturecontains a portion of non-cationized cellulosic fibers.
 25. A dyeingprocess according to claim 21, comprising dyeing the mixture with a dyeselected from the group consisting of a direct dye and a reactive dye.26. A dyeing process according to claim 25, wherein dyeing with thedirect dye involves working at a salt concentration of 2 to 25 g/l. 27.A dyeing process according to claim 25, wherein dyeing with the reactivedye involves working at a salt concentration of up to 80 g/l.
 28. Adyeing process according to claim 21, wherein the mixture is dyed with awool dye and at least one other dye selected from the group consistingof a direct dye and a reactive dye.
 29. A dyeing process according toclaim 28, wherein the wool dye is a metallized dye.
 30. A dyeing processaccording to claim 21, wherein the mixture contains a portion ofnon-cellulosic fibers.
 31. A process according to claim 21, wherein thefibre blend is dyed in the form of a yarn or a part of a yarn.
 32. Aprocess according to claim 21, wherein the fibre blend is dyed in theform of a textile or a part of a textile.
 33. A process according toclaim 32, wherein the fibre blend is dyed in the form of fabric so as toachieve a denim effect.
 34. A fibre blend produced by a processaccording to claim
 21. 35. A fibre blend comprising a portion ofcationized cellulosic fibers and a portion of non-cationized cellulosicfibers, wherein (i) the portion of cationized cellulosic fibers and theportion of non-cationized fibers are coloured with the same dye and,(ii) there is a difference in the coloring intensity between the portionof cationized cellulosic fibers and the portion of non-cationizedfibers.
 36. A fibre blend according to claim 35, wherein the differencein the coloring intensity amounts to 5 to 50 CIELAB units.
 37. A fibreblend comprising a portion of cationized cellulosic fibers and a portionof non-cationized cellulosic fibers, wherein the portion of cationizedcellulosic fibers is colored with a wool dye, and the portion ofnon-cationized fibers is colored by another dye.
 38. A fibre blendaccording to claim 35, wherein the cationized cellulosic fibersincorporate the cationic groups.
 39. A fiber blend according to claim35, wherein the cationized cellulosic fibers are cationized viscosefibers.
 40. A fiber blend according to claim 35, wherein the mixturecontains a portion of non-cellulosic fibers.
 41. A fiber blend accordingto claim 35, which is in the form of a denim fabric.